Stratosphere-troposphere coupling

Earth’s atmosphere is divided in the vertical. People are aware that the troposphere (0-10km) affects the stratosphere (10-50km) but have only recently begun to accept that the stratosphere also influences the troposphere. Although there is now lots of evidence that the stratosphere affects the troposphere, the mechanisms for this influence are not well understood. I suggest one mechanism for the downward propagation of a disturbance from the stratosphere to the troposphere noting the sensitivity of the amount of downward propagation seen to the magnitude of the applied disturbance and the stratospheric response to tropospheric wave forcing. If this mechanism is important then I argue that a well resolved stratosphere is crucial to accurately simulate the affect that wave breaking or solar heating in the stratosphere will have on the troposphere.

I will also briefly discuss the effect that ENSO (sea surface temperatures in the tropics) has on the variability of the tropical lower stratosphere, arguing that the mechanism is via remote forcing rather than simply a vertical extension of forcing on the tropical troposphere.